ALFALFA 



INOCULATED 



Fig. 29. Inoculation or Starvation. 



Each jar contains pure quartz sand to which all the necessary elements 

 for plant growth, except nitrogen, have been added. The alfalfa bacteria 

 supplied by inoculation have taken sufficient nitrogen from the air to produce 

 a healthy growth of alfalfa. The alfalfa plants in the sand receiving no in- 

 oculation have starved for a want of nitrogen. Especially on sandy and 

 other soils, which may lack nitrogen, inoculation is very important. 



37 



